Rainwater runoff durinng rain event

Research

Department of Urban Water Management and Urban Drainage (SE)

Our department covers all aspects related to discharge and treatment of stormwater and wastewater in urban areas

Research Areas

Research focus is the measurement of water and pollutant flows in urban catchments and their mathematical description in models. On this basis, methods for optimizing planning and operation are developed.

Online quality probe in a sewer system (c)
Online quality probe in sewer system

Current research projects

Potential of pollution based real time control in combined sewer systems

Chancen und Herausforderungen von Online-Qualitätsmessungen - eine integrierte Betrachtung

Based on the broad online data basis of two combined sewer overflow tanks in Germany, different control strategies will be developed and their effectiveness in terms of reduction of emitted volumes and pollutant loads will be investigated. The possibilities and limits of quality-based flow control in the combined sewer system will be assessed. Overall, the study should provide a better understanding of the load-specific and hydraulic processes in the combined sewer system and thus make an important contribution to closing the knowledge gap between effluent volume and concentration and furthermore, provide basic information on the implementation of an optimal flow control in combined sewer systems.

Funding: German Federal Environmental Foundation (DBU)
Contact: Anna Bachmann-Machnik, M.Sc.; Dr.-Ing. Ulrich Dittmer
Project Duration: 07/2016-06/2019

Pilot measure Optimization of rainwater treatment at the Abwasserzweckverband Mittleres Jagsttal

By the end of 2024, all combined sewer overflow tanks in Baden-Württemberg will be equipped with measurement devices to record surcharge and overflow periods and frequencies. The Abwasserzweckverband Mittleres Jagsttal has been measuring these values since 2014 on all its combined sewer overflow tanks. In the pilot project, this data is used to optimize the operation of the combined sewer overflow tanks. The aim is to adjust the controlled outflow of the tanks for an optimal utilization of the existing storage volume. As a result, the water pollution can be reduced without the construction of additional tanks. The findings of this project will be applied nationwide.

Detailed project description: Pilot measure Optimization of rainwater treatment at the Abwasserzweckverband Mittleres Jagsttal (pdf)

Funding: Ministry of the Environment, Climate Protection and the Energy Sector Baden-Württemberg (UM)
Contact: Yannic Brüning, M.Sc.; Dr.-Ing. Ulrich Dittmer; Dr.-Ing. Harald Schönberger
Project Partners: AZV Mittleres Jagsttal; RP Stuttgart; UFT Umwelt und Fluid-Technik Dr. H. Brombach
Lieb Ingenieurberatung; Gesellschaft für angewandte Ökologie und Umweltplanung (GefaÖ)
Project Duration: 12/2016-11/2019

Utilization of the measured discharge activity of combined sewer overflows for performance review and improved system planning

In the long term, the measured data of combined sewer overflows collected in Baden-Württemberg should also contribute to a more effective planning of measures in the sense of "rolling planning". However, initial experiences show significant deviations between the actual behavior of the systems on the one hand and the results of quality simulations on the other.

The aim of the project is to show how the pollution load calculation on the basis of measured data can be improved in such a way that the actual behavior of combined sewer systems can be reproduced realistically.

Detailed project description: Utilization of the measured discharge activity of combined sewer overflows for performance review and improved system planning (pdf)

Funding: Ministry of the Environment, Climate Protection and the Energy Sector Baden-Württemberg (UM)
Contact: Dipl.-Ing. Christian Klippstein; Dr.-Ing. Ulrich Dittmer; Dr.-Ing. Harald Schönberger
Project Partners: Abwasserverband Weißach- und Oberes Saalbachtal
Project Duration: 10/2015-05/2019

Rainwater treatment concept of the wastewater association Weißach- and Oberes Saalbachtal in Bretten

Verification, reorganization and optimization of the rainwater treatment concept of the AV Weißach- und Oberes Saalbachtal by recalculation with a sewer quality model. Part of the project is the hydraulic calculation of the main sewer network as well as the review of hydraulic dimensions of the stormwater treatment and overflow structures. The results are compared and checked with the data of the wastewater association and, if necessary, individual solutions are incorporated.

Detailed project description: Rainwater treatment concept of the wastewater association Weißach- and Oberes Saalbachtal in Bretten (pdf)

Funding: Abwasserverband Weißach- und Oberes Saalbachtal
Contact: Dipl.-Ing. Christian Klippstein; Dr.-Ing. Ulrich Dittmer; Dr.-Ing. Harald Schönberger
Project Partner: Abwasserverband Weißach- und Oberes Saalbachtal
Project Duration: 10/2015-05/2019

Detailed project description: Rose Particle (pdf)

Precipitation on impermeable surface (c)
Precipitation on impermeable surface

Rose particle

Development of a robust sensor for the detection of solid loads and particle properties in sewer networks and water bodies

Solids from urban settlements, transported by storm water and combined sewer overflows affect aquatic ecosystems. Solids in urban rainwater runoff can be highly loaded with pollutants (e.g. heavy metals, PAH, MTBT). One measure to increase resource and energy efficiency in rainwater management is the quality-based control of wastewater flows during rainy weather, which separates outflows of different degrees of pollution in real time. In this project, an online sensor will be developed that can be used, for example, for discharge control. In addition to the pure quantity, the size distribution of the particles will also to be recorded.

Funding: Federal Ministry of Education and Research
Contact: Dipl.-Ing. Philipp Baum; Dr.-Ing. Ulrich Dittmer; Dr.-Ing. Harald Schönberger
Project Partner: NIVUS GmbH
Project Duration: 07/2016-12/2018

Investigation of pollution and treatability of urban runoff from an industrial area

Within the framework of this project, the following points will be investigated at a rainwater treatment plant, which treats the rainwater of an industrial area of the city of Freiburg:

  • the occurrence of AFS63 as well as heavy metals and organic trace substances in the surface runoff.
  • the relationships between the indicator AFS63 and selected pollutants.

For this purpose, rain events are sampled and the solids contained in them are examined in different size fractions (< 63μm, < 125 μm, < 250 μm, < 2000 μm) for their pollutant load.

Mittelgeber: Ministry of the Environment, Climate Protection and the Energy Sector Baden-Württemberg (UM)
Ansprechpartner: Dipl.-Ing. Philipp Baum; Dr.-Ing. Ulrich Dittmer; Dr.-Ing. Harald Schönberger
Projektlaufzeit: 01/2016-12/2018

Multi-objective optimization of stormwater networks considering the concept of decentralization

The final aim of this study, is to investigate the relation between the degree of decentralization and cost, reliability, resilience, and sustainability of urban drainage systems considering both grey and green infrastructures. To do that a decentralized layout generator algorithm is developed. All potential green measures (low impact developments) are recognized and introduced to the model. The model is coupled with SWMM model to simulate the hydraulic performance of each design. Then, a multiobjective optimization engine is employed to do the optimization.

Detailed project description: Multi-objective optimization of stormwater networks considering the concept of decentralization (pdf)

Funding: BMBF-DAAD-Sustainable Water Management Scholarship
Contact: Amin Ebrahim Bakhshipour, M.Sc.; Dr.-Ing. Ulrich Dittmer; Prof. Dr.-Ing. Wofgang Nowak
Project Duration: 03/2016-06/2019

Bathing in the river Ruhr

For the bathing season 2019, the early warning system at the lake Baldeney in Essen will be improved to make more accurate predictions of hygienic threshold value violations to ensure safe bathing conditions at a bathing site. In the future, water level measurements at different CSO tanks discharging into the Ruhr River upstream of lake Baldeney will be taken into account. Based on rainfall data and water level measurements collected in the last bathing seasons, together with the results of the microbial investigations at the bathing site, relationships between the data will be examined and recommendations for an adapted early warning system will be developed.

Funding: Ruhrverband
Contact: Anna Bachmann-Machnik, M.Sc.; Dr.-Ing. Ulrich Dittmer
Project Duration: 02-05/2018 and 09-11/2018
Early Warning System (c)
Early Warning System

Completed Research Projects

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SAMUWA Funding (c)
SAMUWA Funding

In the BMBF-funded joint research project SAMUWA, the existing water infrastructure systems were reconsidered and ways were shown to lead the planning and operation of drainage systems to an adaptable dynamic management. For this purpose, planning tools, IT tools and organizational processes were further developed. The results from SAMUWA support municipalities and their drainage companies on the path of converting conventional drainage to intelligent systems with adaptive management of the overall urban hydrological system.

Detailed project description: SAMUWA: The city – a hydrological system in change- Steps towards an adaptive management of the urban water cycle (pdf)

Funding: Federal Ministry of Education and Research
Contact: Anna Bachmann-Machnik, M.Sc.; Dr.-Ing. Ulrich Dittmer
Project Partners:

Bergische Universität Wuppertal, Lehrstuhl Städtebau (LS SB); FH Münster, Institut für Wasser ∙ Ressourcen ∙Umwelt (IWARU); Institut für Automation und Kommunikation, Magdeburg (ifak); Universität Stuttgart, Institut für Landschaftsplanung und Ökologie (ILPÖ); Universität Stuttgart, Institut für Wasser- und Umweltsystemmodellierung (IWS); aqua_plan Ingenieurgesellschaft für Problemlösungen in Hydrologie und Umweltschutz GmbH, Aachen; Dr. Pecher AG, Erkrath; Emschergenossenschaft/Lippeverband, Essen (EGLV); InfraConsult Gesellschaft für Infrastrukturplanung mbH, Stuttgart; Stadt Münster; Stadtentwässerung Reutlingen (SER); Wuppertaler Stadtwerke Energie Wasser AG (WSW)

Project Duration: 07/2013 – 06/2016

Project Homepage SAMUWA

In this project for the German Association for Water, Wastewater and Waste (DWA) Baden-Württemberg a practical guideline and training documents with the topic "operation of combined sewer overflows" were created.

The aim of this project was to provide assistance to small and medium-sized operators in particular in the form of a guideline. In addition to the practical guide, presentation slides were also prepared for the training of operating personnel. In order to ensure that the content is used in practice, representatives of operators, authorities, manufacturers, planners and equipment suppliers have been involved in the project and their experience was taken into account.

Sedimentation tanks are currently the most widely used method for treating surface runoff. The cost-benefit ratio of sedimentation tanks is rather unfavourable in view of the construction work involved and the land consumption. On behalf of the Eigenbetrieb Stadtentwässerung (ESE), badenova AG has designed a new type of plant as a cost-effective and space-saving alternative. The aim of this investigation was to test the effectiveness of this system using measurement technology. In addition to the evaluation of the individual structure, the results were also intended to provide general information on the effectiveness of this type of plants. In addition to the overall efficiency of the solids retention, the effectiveness of the plant for the retention of fine solids (AFS63) was also determined.

Detailed project description: Investigation of the treatment efficiency of innovative rainwater treatment plants (pdf)

Funding: Eigenbetrieb Stadentwässerung Freiburg
Contact: Dipl.-Ing. Philipp Baum; Dr.-Ing. Ulrich Dittmer
Project Partners: bnNETZE GmbH
Project Duration: 08/2014 - 07/2016

The aim of this study was to identify and evaluate technical measures that can effectively reduce emissions of micropollutants from the sewer systems in the catchment area of ​​the upper Körsch river. The total emissions from combined sewer overflows and wastewater treatment plant were considered together and interactions were taken into account. Based on numerical simulations of the sewer network and wastewater treatment plant, solutions were developed that optimally combine measures in both subsystems.

Detailed project description: Study to reduce the input of micropollutants from urban wastewater systems into the river Körsch (pdf)

Funding: Ministry of the Envoronment, Climate Protection and the Energy Sector Baden-Württemberg (UM)
and Landeshauptstadt Stuttgart, Eigenbetrieb Stadtentwässerung Stuttgart
Contact: Dr.-Ing. Marie Launay; Dr.-Ing. Ulrich Dittmer; Dr.-Ing. Harald Schönberger
Project Partners:
Landeshauptstadt Stuttgart, Tiefbauamt, Eigenbetrieb Stadtentwässerung Stuttgart
iat – Ingenieurberatung für Abwassertechnik
InfraConsult – Gesellschaft für Infrastrukturplanung mbH
Project Duration: 01/2012-11/2016

In this project, the emissions from the wastewater treatment plant Böblingen-Sindelfingen as well as the pollution from the catchment area of ​​the river Schwippe were recorded by sampling and online measurements during dry and wet weather. The conditions before and after construction of an additional purification stage at the wastewater treatment plant were examined in two measurement campaigns in order to analyze the effects of the plant with respect to the elimination of organic micropollutants.

The reason for the study was the planned construction of a rainwater treatment facility in the Haid industrial area. In order to compare the effectiveness of different process options in the planning phase, detailed 3D simulations were scheduled. In a first phase of the project, 20 rain events were sampled over a period of six months in high temporal resolution and fully analyzed for their solid content and chemical oxygen demand (COD). For individual events, the concentrations of heavy metals and PAH were also determined.

The project estimated possible effects of climate change on the discharge behavior of combined sewer systems. The core of the project were long-term simulations with the quality model KOSIM. Precipitation data were generated with the stochastic precipitation generator NiedSim-Klima.

To show a range of possible developments, precipitation series were generated for seven locations with different precipitation characteristics in Baden-Württemberg. The behavior of several drainage systems, which differ significantly in terms of their network structure and the characteristics of their discharge facilities were investigated.

Man-made climate change affects the global and regional water balance. This requires adjustments to future water management plans and measures for the use and protection of surface and underground water.

For a planned adaptation strategy of the state of Baden-Württemberg to the consequences of climate change, the Water Research Center Stuttgart, under the coordination of the ISWA, has prepared an expert report for water balance. The report describes adaptation objectives and measures.

First part of this project were intensive measurements of temperature and flow within sewer systems and the adaption of a model to measurement. In a second subproject, the reactivation of an existing wastewater heat exchanger was scientifically monitored.

The subject of the research project was an improved description of the transport of solids in the quality model of the Berlin sewer network. A further aim of this improvement was the description of the interactions between sewer network, sewage pumping stations and storage in the drainage system. The focus was initially on the fundamental study of the possibilities and limits of the modelling of solid transport, including uncertainty analysis.